Construction R-value Calculator
This online calculator calculates the R-value of a large number of common wall and roof constructions given a specified level of insulation. It uses the isothermal planes method to account for thermal bridging of framing material.
R-value, thermal bridging
Basic understanding of construction details is required.
Approximately 15,000 web hits per month, mainly from New Zealand.
Designers and architects, researchers, officials dealing with building regulations
The user selects the appropriate wall and roof design details from a number of drop-down boxes and enters the R-value of the installed insulation product.
The program displays the R-value achieved by the wall or roof construction accounting for all layers of the structure including thermal bridging. (The program also displays the R-value performance in respect to a New Zealand good practice guide.)
Extremely user friendly and quick, very transparent, quite flexible
The list of international construction details is limited, but users are encouraged to submit new ones which will be added to the database
Free, available online.